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  <title>Document</title>
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  <script>

    function Person(name,age){
      this.name=name ;
      this.age= age;
      this.say = function(){
        console.log(this.say);
      };
    }
    let a = new Person('xiaoyan',21)
    console.log(a);
    console.log(a.say);

    //  包装类  都可成对象 都可以加属性;
    let number = new Number(123);
    let str = new String('abc');
    let bol = new Boolean('true');

  </script>
</body>
</html>